Battery charger

STw4102

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6.2

Trickle charge

constant current method.

The trickle voltage threshold and trickle current are defined by OTP configuration bits and

are factory set to 2.9 V and 60 mA by default. Other values are possible, see Section 9:

Factory OTP options on page 24.

6.3

Charging from a wall adapter

The MAIN input is used for charging from a wall adapter or a dedicated USB charger. The

SEL_DC_USB bit (bit 5 of register REG_CHG0) must be set to 0. The fast charge current is

The value of the fast charge current is given by the following formula:

In the constant voltage mode, the charger output voltage is regulated with 1% accuracy. The

charger output voltage is programmable using the REG_CHG0 register, bits 3 and 4 (see

Table 11).

Figure 20.

Main charge mode

Table 11.

Charger output voltage

REG_CHG0[4]

REG_CHG0[3]

0

0

4.10V +/-1%

0

1

4.20V +/-1%

1

0

4.30V +/-1%

1

1

4.35V +/-1%

Trickle

Constant current

Constant voltage

charge

Flag end of

Battery Voltage

Charge current

Fast charge

Maintenance

charge